Cyanine dyestuffs



Patented Nov. 13, 1945 UNITED STATES PATENT OFFICE CYANINE DYES'I'UFFS Douglas James Fry and John David Kendall. lliord, 'hgland, asslgnors to Iliord Limihd, Iiiord, Essex, England, a British company No Drawing. Application January 21, 1938, Se-

ilsflsl zNil. 188,251. In Great Britain January 22.

24 Claims.

October, 1933 there have been described processes in which iive-membered ring compounds containing the grouping tor example, rhodanic acids, have been condensed with a series heterocyciic nitrogen compounds having thioether or seleno-ether groupings or aminovinyl or substituted aminovinyl groupings in the a. or 7 position to a nitrogen atom, or with substances such as N.N-dimethyl-glutaconic-aldehyde-di-anilide-hydrochloride or diaryl-tormamidines and the like, to form intermediate compounds which may themselves be condensed with quaternary salts oi heterocyclic nitrogen compounds containing methyl groups in the u or '7 position to the nitrogen atom to form dyestuii's.

It has also been proposed to' prepare condensation products by condensing a rhodanic acid or like iive-membered ring compound having the 8 cured-1:4

with aldehydes such as, ior example, acetaldehyde, benzaldehydes or aminobenaaldehydes.

It is believed that in each of these reactions the reaction takes place on the cyclomethylene group 01' the flve-membered ring compounds.

In the case of rhodanic acid the compounds yielded are of the general type:

where D represents'the remainder of a heterocyclic ring condensed on to the rhodanic acid compound as above,

n=0 or 1, and m=0, 1 or 2 and R=hydrosen,

aikyl, aryl or sralkyl group, and R1=a1kyl,

or oi the general type:

where n=0, 1 or 2, R=H, alkyl. aryl or aralkyl and R1=H. aiwl or acyl or oi the general type:

A-OH=0S\ c=s O= -N where A is the remainder 01' an aldehyde.

In the specification accompanyins British Patent Application No. 31191/36 a process has been described according to which compounds containing the same grouping, i. e.

(an-a fan. l q-coll! IIT-COH= H may be condensed in the presence of an acid anhydride e. g. acetic anhydride, and an acid binding agent, for example pyridine, with quaternary salts of heterocyclic nitrogen compounds having a methyl group in the a or 7 position to the nitrogen atom.

In this case it is believed that the reaction takes place with the formation of a compound-oi the type:

where D represents the remainder of a heterocyclic ring, n=0 or i and R=H or an alkyi, aryl or aralkyl group, R1 and Rz=alkyl and Y=remainder of a flve-membered ring.

In the specification accompanying British Patent Application No. 31192/36 a process has been described according to which the compounds produced according to the method of British Patent Application No. 31191/86 comprising a five-membered ring compound containing the system:

are treated with an alkyl salt to convert the thione or selenone group or the flve-membered ring into a reactive grouping and the compounds are then condensed with 'a large number of other compounds as described therein.

It has now been found that rhodanic acids and similar five-member ring compounds containing the system:

including the compounds obtained according to British patent specifications No. 426,718, filed 3rd October, 1933, and No. 428,359, filed 22nd March, 1935 (divisional of 426,718 filed 3rd October, 1933) and British patent application No. 31192/36 and which may all be regarded as corresponding to the general formula:

C=S (or Be) when Y=O, S or Be, R=alkyl. aryl or aralkyl and Z represents H: or the other groupings attached to the flve-membered ring in the compounds produced according to the earlier specifications referred to above, also react with alkyl salts so that the thione or selenone grouping in the fivemembered ring is converted into a reactive grouping which can be reacted with compounds containing complementary reactive groupings as described in any of the above-mentioned specifications and in specifications of British Patents No. 431,186, No. 431,187, and No. 432,628, filed 12th June, 1935 (divisionals of No. 431,141, filed 23rd December, 1933), No. 425,609, filed 12th September, 1933, and No. 461,688, filed 27th January, 193'1 (divisional of No. 461,688, filed 16th August, 1935), and Nos. 424,559 and 431,141, to yield new dyestufls.

The present invention accordingly comprises a method of producing dyestuffs by condensing a five-membered heterocyclic ring compound of the ype:

where R my be alkyl, aryl or aralkyl groups, Y may be 0, S or Be, and Z may represent H: or a group corresponding to either of the following formulae:

where R, R1 and B: may be alkyl. aryl or aralkyl a,sss.oos

roups. Y may be 0, S or Be and D is the remainder of a heterocyclic nucleus, or

where R1 may be alkyl, aryl or aralkyl grouping and N may be contained in a heterocyclic ring or part of a noncyclic chain or part of an amino group external to a carbocyclic ring which forms part of the chain and 1:. may be 0 or a positive integer (e. g., 1, 2, 3, 4 or 5), or

c A-CH= where A represents the remainder of an aldehyde. with an alkyl salt to convert the thione or selenone grouping into a reactive group and condensing the resulting compound with one of the following types of compounds:

(a) A flve-membered ring compound containin the system:

where R1, R2 and B: may be alkyl, aryl or aralkyl groups or R1 and B: may be part of the same arylene ring.

(d) Carbocyclic compounds containing a hate methylene group.

(2) Acids or esters of the type:

where X=hydrogen or a mono-valent substituent, R=hydrogen or an alkyl or similar group and n=0 or 1.

(f) Anhydrides of acids of the general formula:

where X is hydrogen or a monovalent grouping, and n is 1 or 2.

(g) Ammonia or amidines or hydrazlnes or di amines or their salts.

According to a further feature of the invention when the flve-membered ring compounds containing the system:

which are condensed with the quaternary salt of the compounds of the formula:

Z=O-Y\ l o=s (or so 0:

correspond to the general formula:

Hie-Y els/ the resulting product conforms to the same general formula as the starting material and so may be treated with an alkyl salt and condensed with Iii-O HI which also corresponds to the general formula:

the product will once more conform to the general formula of the starting material, and by proceeding in this way the condensation may be repeated as often as desired; the final product obtained by such a series of condensations may be again condensed according to the invention with any of the other groups by which it is possible to obtain dyestufls comprising two nuclear groups, for example, heterocyclic nitrogen nuclei, linked by a chain oi. any desired number of keto-thiazoline rings, which chain may also include other rings such as cyclopentadiene rings or methine groups or nitrogen atoms according to the condensation carried out.

It is believed that in the first part of the process the thione group is converted into a reactive thioether grouping which may then react with any of the other groupings as described in the prior specifications referred to above.

The condensation may be carried out by first carrying out the reaction with the alkyl salt and then reacting the resulting compound with the other compounds or in the case where quaternary salts oi heterocyclic nuclei and the like are emplayed, the two bases may be fused together with the alkyl salt and the reaction completed by heating in the presence of an acid binding substance, for example, pyridine, as described in the specification of British Patent No. 438,420 filed th November. 1935.

Examples of five-membered ring compounds of the formula:

O=S (or So) which may be employed in accordance with this invention are the 4-keto-2-thio \or seleno) tetrahydro-thlazoies, 4-keto-2-thio (or seleno) tetrahydro-oxaaoles, i-keto-il-thio (or seleno) tetrahydro-selenazoles or their N-alkyl, N-aryl and N-aralkyl derivatives and their derivatives as obtained by the processes referred to above.

Where heterocyclic nitrogen nuclei are referred to in this specification they may be any of those which have been used or proposed for use in the many processes for the production of cyanine and similar dyestufl's, for example, thiazoles, oxazoles, selenazoles and their polycyclic homologues such as those of the benzene, naphthalene, acenaphthene and anthracene series; pyridine and its Polycyclic homologues such as quinoline and naphthaquinoline; lepidines; indolenines; diazines, such as pyrimidines and quinazolines; diaaoles (e. g. thio-pE-dlazole) oxazollnes, thiazolines and selenazollnes. The polycyclic compounds of these series may also be substituted in the caroocvclic rings with one or more groups such as alkyl, aryl, amino. hydroxy. alkoxy and methylene dioxy groups.

mExamples of the compounb having the groupwhich may be condensed with the compounds of the first group according to our invention are those enumerated in the specification oi British Patent No. 426,718, filed 3rd October, 1933, namely. oxindoles, pyrazole-S-ones. hydantoin. thiohydantoin, 'p-hydantoin. \p-thio-hydantoin, dihydroxythiazole and their N-substitutlon products.

The dyestuffs produced in accordance with the present invention are sensitisers for photographic silver halide emulsions and the invention also includes photographic silver halide emulsions sensitised with the dyestufls produced in accordance with the present invention.

The invention is illustrated by the following specific examples which are given by way of example only. The equations given in the speciflcation illustrate what is believed to be reactions taking place, but we do not bind ourselves to the equations given.

Emmi

A. Preparation of 3-ethol-2-thio-4-keto-5-(N- methuldihydrobenzozazolylidene) tetrarwdrothiaeolc 16.5 gms. of l-me'thylthiolbenzoxazole and 18.6 sins. of methyl-p-tolucne suipbonate were iused together for 3 hours at -140" C. After cooling 16.3 ms. of N-ethyl rhodanic acid and ccs. of pyridine were added and the mixture was gently heated to efiect solution and then gently boiled under a reflux condenser for about 25 minutes. The yellow mixture was then diluted with water until no further precipitate was formed and the precipitate was filtered of! an washed with water and ether and recrystallised from methyl alcohol as yellow crystals melting at 212 C. The reaction may be illustrated as follows:

B. Preparation of 3.3-diethwl-4.4'-diketo-5.5'-di- (N-methuldihudro benmazolyiidene) -thiazolino cuanine iodide 7.7 Bins. oi the product obtained by condensing N-ethal-rhodfl-nic acid and l-methyl-thiolbenzoxazole-methyl-p-toluene sulphonate was fused together with 20 ms. of methyl-p-toluene sulphate at 120 C. for 2% hours. The mixture was allowed to cool, 5 ms. of malonic acid and 150 cos. of pyridine were then added and the mixture was gently heated on a water bath for 45 minutes when a rose colour developed. The mixture was then poured into a beaker containing a dilute aqueous solution of 30 gms. of potassium iodide. A bronze precipitate was formed which was filtered and washed with water. spirit and ether and recrystallised as bronze crystals, melting at 260 C. with decomposition and giving purple-red alcoholic solutions. The reaction may be illustrated as follows:

c=c-s l C=B+CHmC1H180a -b N $15!: 0: N

0! malonic acid and 15 cos. of pyridine but pouring into water instead of potassium iodide, yielding 0.12 gm. of golden crystals, melting at over 310 C.

This dye is a sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver lode-bromide emulsion to about A 6300 A. with a maximum at about )i 6000 A.

3.3'-diethy1 4.4 diketo-5.5'-di(2 methyldihydrobenzthiazolylidene 1 ethylidinelthiazolino-cyanine bromide was also prepared by the method of Example IB from 0.87 gm. of 2 thlc- 3-ethyl-4-keto-5 (2 methyldlhydrobenzthiazolylidene-l-ethylidene) tetrahydrothiazole prepared from l-lp-acetanilidovinyl benzthiazolemethyl-p-toluene sulphonate and N-ethylrhodanic acid according to the method of Example 3A, 3 gms. of methyl-p-toluene sulphonate and 0.5 gm. of malonic acid and 15 cos. of pyridine using potassium bromide in place of the potasslum iodide yielding 0.05 gm. of golden crystals, melting at 285 C. and giving an olive green solution in alcohol.

3.3-diethyl-4.4'-diketo-5.5-di(2 methyldihydrobenzthiazolylidene-l-ethylidene) thiazolinocyanine bromide was prepared according to the method of Example 113 from 0.84 gm. of 2-thio-3- cl m clmsol +KI r-" n 5 0,11.

ECOOigH clmsou .7... :1 .I 1

o 0' 0=c-s\ s-o=o l c-oa=c l (5m 0: 7 1 =0 (13H fil g'n so l 1 7 7 I +K.CHS0 were 3.3'-diethyl-4.4'-diketo-5.5'-di- (Z-methyldilw robenzthiazolylidene) thiazolino cyanine p- Jlliene sulphonate was prepared in a similar manner to that described in Example 18 from .75 gm. of 2-thio-3-ethyl-4-keto-5-(z-methyldiydrobenzthlazolylidene) tetrahydrothiazole, preared according to the method 01' Example IA 0m N-ethyl-rhodanic acid and l-methylthiol enzthiazole methyl-p-toluene sulphonate, 3 rams oi methyl-p-toluene sulphonate, 1.0 gm.

ethyl-*i-keto-5-(2 methyldihydrobenzthiazolylidene-Lethylidene) tetrahydrothiazole prepared from 1--acetanilido-vinyl-benzthiazole-methylp-toluene sulphonate and N-ethyl-rhodanic acid according to the method of Example 3A, 3.0 gms. of N-ethyl-rhodanic acid, 0.5 gm. of malonic acid and 15 cos, of pyridine using potassium bromide in place of the potassium iodide, yielding 0.2 gm. of blue-black crystals, melting at over 290 C. and givin a Ineen snllitirm in alnnhni a,ese,eee

mam-a2 O Br 7.5 grams oi the product produced according to Example In and 8.75 girls. l-methyl-benzthiasole and 20 gms. oi methyl-p-toluene suiphonate were fused together at 180 C. ior 2% hours. The mixture was then allowed to cool and 150 sea. of pyridine were added and the mixture was reheated on a boiling water bath to effect solution and then gently boiled under a reflux condenser for a further 20 minutes. The mixture was then poured into a large bulk 01' water containing potassium bromide. Orange crystals separated out, which were filtered ofl. wash'ed with spirit and ether and extracted by boiling out with methyl alcohol. The dyestuil was then recrystallised from methyl alcohol yielding small red-brown crystals with blue-green reflex, melting at 291 C. with decomposition.

The reaction is believed to take place as follows:

on. o:

This dye is a sensitiser tor photographic emul- 7o sions and extends the sensitivity range 0! a silver lode-bromide emulsion to about 7 5800 A.

The following products were also obtained by the same general method as described in Example 2 iron the compounds indicated. In each case the substituted tetrahydro thlasole was pre pared by the general method described in Example 1A from the corresponding N-alkylrhodanic acid and the quaternary salt at the corresponding methyl-thiol heterocycllc nitrogen compound.

It the p-toiuene sulphonates oi the dye were required water was employed in the place of the potassium bromide and it other salts were required the corresponding alkali salt was used.

2'-ethyl-8-methyl-4-keto-5 (2 methyldi-hydro bensoxazolylidine) thiasolino oxacyanine iodide from 0.70 gm. 0! the 2-thio-8-methyl-4-keto-li-(il-methyldihydrobenzoxazolyiidene) tetrahydrothiazole, 0.33 gm. oi l-methylbenaoxesole and 4 girls. oi ethyl-p-toluene sulphonate but 15 cos. or alcohol and 0.5gm. of anhydrous sodium acetate in place of the pyridine yielding 0.18 gm. of small dark red crystals, melting at 291' G.

This dyestufl' is.a sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver lode-bromide emulsion to about A 8200 A. with a maximum at about i 5600 A.

3-methyl-2' -ethyl-4-keto-5- (2-methyldihydrobenzthiazolylidene) thiazolino thiacyanine ptoluene sulphonate from 0.78 gm. of 2-thio-8- methyl-4-keto-5- (2 -methyldlhydrobenztliialolylidene) -tetrahydrothiazole, 4 gms. of ethyl-p-toluene suiphonate and 0.37 gm. of l-methylbenzthiazole, yielding 0.79 gm. 01 small red crystals, having a gold reflex melting at 283 C.

This dyestuii is a sensitiser for. silver halide photographic emulsions and increases the sensitivity range 0! a silver iodo-bromide emulsion to about a 6200 A. with a maximum at about A 5400 A.

3.2'-diethyl-4-keto-5 (2 methyldihydrobenzthiazolylidene) thiazolinothiacyanine P toluene sulphonate was prepared irom 0.77 gm. oi 2- 4o thio-8-ethyl-4-keto-5-(2 methyldihydrobenzthiasolylidene) -tetrahydrothiazole and the same quantities of the other compounds as in the preceding example, yielding 0.00 gm. of small scarlet needles. melting at 280 C.

This dyestufl is a sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver iodo-bromide emulsion to 22:33). 6200 A. with a maximum at about A 3.i'-diethyl-4-keto-5 (2 methyldihydrobenzthiazolylldene) -thiazolino-2' quinocyanine bromide from 0.75 gm. of 2-thio-3-ethyl-4-keto-5- (2 methyldihydrobenzthiaaolylidene) tetrahydrothiazole, 0.36 gm. 0! quinaldine, 4 ms. of ethyl-p-toluene sulphonate and 15 cos. oi pyridine, yielding 0.29 gm. of dark maroon crystals, melting at 271' C.

This dye is a sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver iodo-bromide emulsion to about A 6400 A. with a maximum at about A 5400 A.

3.1'-diethyl-4-keto-5-(2 methyldihydrobenzthiazolylidene) thiazolino 4' quinocyanine iodide was prepared similarly to the preceding example, but using 0.36 gm. of lepidine in place 0! the quinaldine and potassium iodide solution in place of the potassium bromide solutiom used in Example 2 yielding 0.50 gm. or dark blue crystals melting at 288-9 0.

This dyestui! is a sensitiser for photographic silver halide photographic emulsions and extends the sensitivity range of. a silver iodo-bromide emulsion to about A 0300 A. with a maximum at about a 0000 A.

3-methyl-1'-ethyl-4-keto- 5 (2-metbyidihydroquinolylidene) yldihydrobenzthiaaolylidene) thiazolino 2'- quinocyanine-p-toluene sulphonate was also prepared from 0.78 gm. the corresponding 2-thio- 3 methyl 4 keto (2 methyldihydrobenzthiaaoiylidene) -tetrahydro thiazole and the same quantities of the other compounds as used in the preceding examples yielding 0.12 gm. of shining dark green crystals, melting at 278 C.

This dyestui! is a sensitiser for silver halide photographic emulsions and extends the sensitivity range oi a silver iodo-bromide emulsion to about A 6200 A. with a maximum at about A 5600 A.

3.2 diethyl 4 keto 5 (2 methyldihydrobenzthiazolylidene) thiazolinooxacyanine p toluene sulphonate from 0.77 gm. oi 2-thio-3- ethyl 4 keto 5 (2 methyldihydrobenzthiazolylidene) tetrahydrothiaaole, 0.33 gm. of 1- methylbenzoxazole, 4 gms. of ethyl-p-toluene sulphonate and 15 cos. of pyridine yielding on crystallization from methyl alcohol 0.19 gm. of scarlet matted needles melting at 288 C.

This dyestufl is a sensitiser for photographic silver halide emulsions and increases the sensitivity range of a silver lode-bromide emulsion to about A 6200 A. with a maximum at about A 5200 A. It also extends the sensitivity range of a silver chloride emulsion to about A 5400 A with a maximum at about A 5100 A.

3-methyl-2'-ethyl-4-keto-5 (2-methyidihydrobenzthiazolylidene) thiazoiino oxacyanine-p-toluene sulphonate from 0.73 gm. of 2-thio-3-methyl-4-keto-5- (2-methyldihvdrobenzthiazolylidene) tetrahydrothiazole and the same quantities of the other compounds as in the preceding examples, yielding 0.42 gm. of dye crystallized from methyl alcohol as small brick red crystals melting at 292 C. with decomposition.

This dyestufl is a sensitiser for silver halide photographic emulsions and extends the sensitivity of a silver iodo-bromide emulsion to about A 6200 A. with a maximum at about A 5200 A. It also extends the sensitivity of a silver chloride emulsion to about A 5400 A. with a maximum at about A 5100 A.

3.2 diethyl 4 keto 5 (2 methyldihydrobenzthiazolvlidene) thiazolino-seieno cyanine-p-toluene sulphonate from 0.75 gm. of 2- thio 3 ethyl 4 keto 5 (2-methyldihydrobenzthiazolylidenel tetrahydrothiazole, 0.49 gm. of l-methylbenzselenazole and 3 gms. ethyl ptoluene sulphonate and 15 cos. of pyridine yielding 0.29 gm. of small orange crystals, melting at 258 C. The filtrate from the crystals was treated with potassium bromide and a iurther crop of 0.20 gm. of crystals 01' the bromide salt were obtained.

The dyestuil' is a sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver iodo-bromide emulsion to about A 5800 A. with a maximum at about A 5400 A. v

3 methyl 2' ethyl 4 -keto 5 (1 meththiazolinooxacyanine bromide from 0.72 gm. of 2-thio-3-methyl-4- keto 5 e (1 methyldihydroquinolylidene) tetrahydrothiazole, 0.33 gm. oi i-methylbenzoxaaole and 4 gms. or ethyl-p-toluene suiphonate using 15 cos. of alcohol and 0.5 gm. of sodium acetate in place of pyridine, yielding 0.23 gm of dark olive green crystals, melting at 267 C.

, This dyestufl is a sensitiser for silver halide photographic emulsions and increases the sensiaseaoas tivity 0! a silver lode-bromide emulsion to about A 6200 A. with a maximum at about A 5600 A.

8.2 diethyl 4 keto 5 (1 methyldihydroquinolylidene) -thiazolino-thiacyanine iodide from 0.75 gm. oi' 2-thio-3-ethyl-4-keto-5-(1- methyldihydroquinolylidene) tetrahydrothiasole, 0.37 gm. oi I-methylbenzthiazoie, 4 gms. of ethyl-p-toluene sulphonate and 15 ccs. oi pyridine, yielding 0.23 gm. of dark olive green crystals, melting at 284 C.

This dyestuii is a sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver iodo-bromide emulsion to about A 6600 A. with a maximum at about A 5700 A.

8.2'-diethyl 4 keto-5-(1-methyldihydroquinolylidene) -thiazolinooxacyanine iodide from 0.75 gm. of 2-thio-3-ethyl-4-keto-5-(l-methyldihydroquinolylidene) -tetrahydrothiazole, 0.33 gm. oi l-methylbenzoxazole, 4' gms. oi' ethyl-p-toluene sulphonate and 15 cos. of pyridine. yielding 0.21 gm. of dark olive green crystals, melting at 264 C. with decomposition.

This dyestufl is a sensitiser for silver halide photographic emulsion and extends the sensitivity range ot a silver icdo-bromide emulsion to about A 6200 A with a maximum at about A 5600 A.

3.1'-diethyl-4-keto- 5 -(1-methyldihydroquinolylidene) -thiazolino-pseudo-cyanine iodide from 0.75 gm. of 2-ti'1io-3-ethyl-4-keto-5-(I-methyldihydroquinolylidene) tetrahydro thiazoie, 0.86 gm. of quinaldine, 4.0 gms. of ethyl-p-toluene sulphonate, yielding 4.0 gms. or ethyi-p-toluene sulphonate yielding 0.03 gm. of dark olive green crystals, melting at 275 C.

This dyestuil is a sensitiser for silver halide photographic emulsions and extends the sensitivity range or a silver lode-bromide photographic emulsion to about A 6600 A. with a maximum at about A 5600 A.

3-methyl-2-ethyl-4-keto-5- 1 -me thyldihydroquinolylldene) -.thiazolinothiacyanlne iodide from 0.72 gm. oi 2-thio-3-methyl-4-keto-5-(i-methyldihydroquinolylidene) -tetrahydrothiazole, 0.37 gm. of i-methylbenzthiazole, 4 gms. of ethyl-ptoluene sulphonate and 15 cos. of pyridine yielding 0.27 gm. of dark brown green crystals, melting at 276 C.

This dyestufl is a sensitiser for photographic silver halide emulsions and extends the sensitivity range of a silver iodo-bromide emulsion to about A 6700 A. with a maximum at about A 5700 A. r 3-metl'iyl-2'-ethyl-4-l;eto-5-(ii-methyldihydroquinazolylidene i-l -thiazolinotluacyanine p-toluene sulionate from 0.72 gm. of 2-thio-3-methyl- 4-keto-5-(3 methyldihydroquinazolylidene-4-)- tetrahydrothiamle, 0.37 gm. of l-methylbenzthiazoie 4 gms. ethyl-p-toiuene sulphonate and 15 cos. of pyridine yielding 0.41 gm. of brick red matted crystals, melting at over 300 C.

The formula of the dye is believed to be:

This ammo is a sensitiser m1- sflver halide photographic emulsions and extends the sensitivaasspes ity range of a silver iodo-bromide emulsion to about A 0200 A. with a maximum at about A 5000 A.

3.2'-diethyl-4-keto- -(8-methyldihydroq 1n. asolylidene-4-) -thiaaolino thiacyanine-p-toiuene sulphonate irom 0.75 gm. 2-thia-8-ethyi-4-ketoii-(s-methyldihvdroouinaaolylidene 4) -tetrahydrothialole, and the same quantities of the other compounds as in the previous example, yielding 0.80 gm. of dark green brown crystals, melting at over 800' C.

This dye is a sensitiser for silver halide photographic emulsion; and extends the sensitvity range of a silver iodo-bromlde emulsion to about A 0200 A. with a maximum at about A 5700 A.

3-methyl-2'-ethyl-4-keto-5-(ii-methyldihydroquinazolylidene 4 )-thiamlino-oxacyanine-ptoluene sulphonate from 0.72 gm. of 2-thio-8- methyi-4-keto-5-i3 methyldihydroquinaaolylidene-4-) -tetrahydrothiazole, 0.33 gm. of i-methylbenzoxazole and 4 ms. 01' ethyl-p-toluene sulphonate but using cos. of alcohol and 0.5 gm. of anhydrous sodium acetate in place of the pyridine yielding 0.24 gm. oi brown matted crystals, melting at 810 C.

This dye is a sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver iodo-bromide emulsion to about A 6400 A. with a maximum at about A 5600 A.

3.2'-diethyl-4-keto o-iii-methyldihydroquinazolylidene-4-) thiazoiino oxacyanine bromide from 0.75 gm. of 2-thio-3-ethyl-4-keto-5-(3- methyldihydroquinazolylidene 4 )-tetrahydrothiazole, 0.33 am. 01' l-methylbenzoxazole, 4 gms. of ethyl-p-toluene sulphonate, 0.3 gm. of anhydrous sodium acetate and 15 sea. 01 alcohol and pouring the mixture after boiling into a solution of potassium bromide, yielding 0.4 gm. of small olive green crystals. melting at 280 C. with decomposition.

'Ihis dye is a sensitiser for silver halide photographic emulsions and extends the sensitivity rangeoi a silver lode-bromide emulsion to about A 5000 A. with a maximum at about A 5500 A.

3.methyl-1'-ethyl-4-lreto-5-(3-methyldlhydroquinaaoly1idene-4-) -thiazolino--cyanine-p-toluene sulphonate trom 0.72 gm. of Z-thio-S-methyl- 4-keto-5-(8 methyldihydroquinazolylidene-4-) tetrahydrothiazole, 0.36 gm. of quinaldine, 4 arms. of ethyl-p-toluene sulphonate and 15 cos. oi pyridine, yielding 0.06 gm. of deep olive green crystals, melting at 297 C. with decomposition.

This dye is a sensitiser for silver halide photographic emulsions and extends the sensitivity range of silver lode-bromide emulsion to about A 6300 A. with a maximum at about A 5300 A.

3.l'-diethyl-4-keto-5-(3 methyldihydroquinazolylidene-4-) -thiazolinoi1 -cyanine-i toluene sulphonate, from 0.75 gm. of 2-thio-3-ethyl-4- keto-5-(3-methyldihydroquinazolylidene-4-l -tetrahydrothiazole, 0.30 gm. of quinaldine. 4 gms. oi ethyl-p-toluene sulphonate and 15 cos. of pyridine, yielding 0.18 gm. of golden brown crystals, melting at 290 C. with decomposition.

This dyestui! is a sensitiser for photographic silver halide emulsions and extends the sensitivity range 01 a silver iodo-bromide emulsion to about A 6500 A. with a maximum at about A 5900 A.

Exam: 3

4. Preparation of s-ethul-z-thio-l-keto-i-tlmethyl-(.S-methulene dio-W-dihwdrobemthiozoiylidenc-I-ethvlidene) ietro-hydro-thtaeole 19.3 gms. oi 1-methyl-4.5-methylenedioxybenzthiazoie and 10.6 gms. methyl-p-toluene sulphonate were iused tosether for 3% hours at Mil-150 C. The mixture was then allowed to cool and 20 gms. oi diphenyl-iormamidine and cos. of acetic anhydride were added and the mixture was boiled under a reflux condenser ior about 30 minutes. 18 gms. oi N-ethyl-rhodanic acid and 100 cos. of pyridine were then added and the mixture was again boiled for 30 minutes. A precipitate separated out which was filtered off. washed with spirit and ether and purified by boiling out with methyl alcohol leaving green crystals melting at 305 C. and giving a purple red solution. The reaction may be illustrated as iollows:

8. Preparation of 3.3 diethwl 4.4'-diketo-5.5'- di-(N-methvl 4.5 methulene-dioru-dihudrobenzthiazolvlidene- 1 -ethylidene) thlaeolino- 9.4 gms. oi the product produced according to allowed to cool and, 58.8 ms. or diphenyl-torm- 3A above and 40 gms. of methyl-p-toluene sulamidine and 300 cos. of acetic anhydrlde were phonete were fused together for 2 hour at 130 added and the mixture was boiled for twenty minc. The mixture was then cooled and 5 gm. of utes. gms. of N-ethyl-rhodanic acid and son maionic acid and cos. oi! pyridine were added cos. of pyridine were then added and the mixond the mixture gently heated for 45 minutes on ture boiled under a reflux condenser for thirty a water bath to effect solution. 011 solution of the minutes. A dyestufi was precipitated. The mixmelt, a. dyestufi separated out. This was filtered 25 ture was then diluted by pouring into a large bulk oil from the liquors, washed with spirit and ether of spirit when further dyestufl precipitated. This and extracted with benzene leaving dark cryswas filtered oil and washed with spirit and ether tale. The reaction may be illustrated as follows: and purified by boiling out with methyl alcohol,

HI H

:Hz 01H; 013180:

iiififi o.

Exmnr: 4 so 8 Purple crystals. melting at 273' c., and,

giving red alcoholic solutions. The reaction may .4. Preparation of 3-eth1 l-2-thio-4-keto-5-(N- be illustrated as follows:

methvl-benzthiazolyltdene- 1 -ethylidene) -tets rahydro-thiazole NOsHl eon-00 a c-om n o of methyl-p-toluene eulphonate were fused toether for 3 hours at C. The mixture was 76 Q, e, I figfiggi spasms I I I n on- :OIHIEOI mE-o-s --.-----------..----------------.i

\ ills CrHi Br 8.4 ms. or the product obtained according to 4A above, 4.0 gins. of l-methylbenzthiazole and 40 gms. oi methyi-p-toluene sulphonate were fused together for 2 hours at Mil-150 C. The mixture was then allowed to cool and 150 ccs. of pyridine were added, after which the mixture was heated gently to effect solution, and then boiled gently for 25 minutes. The mixture was then poured into a solution oi potassium bromide in water when a precipitate formed. Thi was filtered off, washed with spirit and ether and extracted with benzene and then methyl alcohol, to yield small dark green crystals melting at 283 C. with decomposition. The reaction may be illustrated as follows:

I OH:

mum-st Preparation of .lz-dlcthyl-l-mo-s-tN-methyldill! lidcac- 1 .anwume) -thioaolinothiocyoaine bromide s o-on-o 0- -1 Oa H| Br 8.4 gun. or the product obtained according to Example 4A above, 4.0 gm. of methylbenzthiazole and 40 ms. or ethyl-p-toluene sulphonate were fused together at 140 C. 1'0! 8% hours. The mixture was then allowed to cool and 150 cos. of pyridine were added, after which it was boiled gently for 25 minutes. The mixture was then poured into a. solution or potassium bromide in water. A precipitate formed, which was filtered ofl, washed with spirit and ether and extracted with benzene and then methyl alcohol yielding small green crystals, melting at 274 C. with decomposition.

The following preparations were also carried out in similar manner.

Except where otherwise stated in each case the fi-substltuted tetrahydrothiazole compound was made from the corresponding amino-vinyl substituted quaternary salt of the corresponding heterocyclie nitrogen compound and the corresponding N-alkyl rhodanic acid according to the method of Example 3A or 4A.

In the case of the para-toluene sulphonate salts of the dyes the reaction mixture alter the boiling step was poured into water or crystallised direct and in the case of the other salts, the mixture was poured into a solution of the appropriate alkali salt, e. g. potassium iodide.

3-methyl-2 -ethyl-4-keto-5- l -methyldihydroquinolylidene 2 ethylidene) lazolinothiacyanine bromide from 0.79 gm. of 2-thio-3-methyld-keto-S- (1-methyldihydroquinolylidine-2-ethylidenc) -tetrahydrothiazole, prepared by the condensation o! quinaldine mcthiodide and 5-acetanilidomethenyl-N-methylrhodanic acid in the presence oi pyridine, 0.37 gm. of l-methylbenzthiazoie, 4 gms. oi ethyl-p-toluene sulphonate and cos. of pyridine yielding 0.52 gm. of slate-blue matted crystals, melting at 271 C.

The formula of this dye is believed to be as follows:

00H: Br

The dyestufl is a sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver lode-bromide emulsion to about A 7600 A. with a maximum at about i seen A.

3.2-diethyl-4-keto-5-il-ethyldihydroquinolylldene 2 ethylidene) -thiazollnothiacyanine bromide from 0.88 gm. of 2-thio-3-ethyl-4-ireto-5- 15 ti-ethyldihydroquinolylidene-2-ethylldene) tetrahydrothiazole, 0.37 gm. oi l-methylbenzthiazole, 4 gms. of ethyl-p-toluene sulphonate and 15 cos. of pyridine, 0.26 gm. of dark blue matted crystals, melting at 256 C.

This dyestuil is a sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver iodo-bromide emulsion to about A 7600 A. with a maximum at about 3-methyl-1 -ethyl-4-keto-5- l-methyldihydroquinolylidene-2-ethylidene) thiazolino t cyanine bromide from 0.79 gm. oi 2-thio-3-methyl- 4-keto-5-(1-methyldihydroquinolylidene-Z-ethylidene) -tetrahydrothiazole, prepared by condensing quinaldine methiodide with -aoetanilidomethenyl-N-methylrhodanic acid in the presence of pyridine, 0.36 gm. of quinaldine, 4 gms. of ethyl-p-toluene sulphonate and ccs..of pyridine yielding 0.18 gm. of dark blue matted crystals, melting at 251 C.

3-ethyl-2' -methyl-4 -keto-5 -(1 .3.3 -trim'ethylindolylidene 2 ethylidene) -thlazolinothiacyanine bromide from 0.86 gm. of 2 thio-3-ethyl-4-keto- 5- 1 .3.3-trimethy1indolylidene-Z-ethylidenel -tetrahydrothiazole, 0.37 gm. of l-methylbenzthiazole, 3 gms. of methyl-p-toluene sulphonate and 15 ccs. of pyridine yielding 0.22 gm. of green crystals, melting at 257 C.

This dyestufl is a sensitiser for silver halide photographic emulsions and extends the sensitivity range oi a silver iodi-bromide emulsion to about A 6600 A. with a maximum at about A 6100 A.

3-methyl-2 -ethyl-4-keto-5-(1.3.3-trimethylindolylldene-2-ethylidene) thiazolinothiacyaninep-toluene sulphonate from 0.83 gm. of 2-thio-3- methyl-4-keto-5- r 1.3.3-trimethyl dihydroindolyl idene ethylidene) -tetrahydrothiazole, 0.3? gm. of l-methylbenzthiazole, 3 gms. of ethyl-p-toluene sulphonate and 15 cos. of pyridine yielding 0.51 gm. of dark olive-gree crystals, melting at over 306' C.

This dyestuii is a sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver iodo-bromide emulsion to about A 6600 A. with a maximum at about A 6000 A.

3 methyl 2'-ethyl-4-keto-5-(1.3.3-trimethyldihydroindolylidene 2 ethylidene) thiazolinooxacyanine bromide from 0.83 gm. of 2-thio-3- methyl 4 keto 5 (1.3.3-trimethyldihydroindolylidene-2-ethylidene) tetrahydrothiazole and 0.33 gm. of l-methylbenzoxazole, 3-gms. of ethylp-toluene sulphonate and 15 cos. of pyridine, yielding 0.18 gm. of small green crystals, melting at 271 C.

This dyestuil' is a sensitiser for silver halide photographic emulsions and extends the sensi tivity range of a silver lode-bromide emulsion to about A 6300 A. with a maximum at about A 5800 A.

3-1'-diethyi 4 keto-5-(1.3.3-trimethy1dihydroindolylidene 2 ethylidene) thiazolino-ucyanine-p-toiuene-sulfonate from 0.86 gm. of 2- thin 3 ethyl-4-keto-5-(1.3.3-trimethyidihydroindolylidene 2 ethylidene) -tetrahydrothiazole, 0.36 gm. of quinaldine, 3 gms. of ethyl-p-toluene sulphonate, 15 cos. of pyridine, yielding 0.11 gm. of brown-gold crystals, melting at 272 C.

3-methyl 2' ethyl-4-keto-5-(2-methyldihydrobenzthiazolylidene-l-ethylidene) thiazolinothiacyanine bromide from 0.80 gm. of 2-thio-3- methyl 4 keto-5-(2 methyldihydrobenzthiazolylidene-l-ethylidene) -tetrahydro-thiazole, 0.37

gm. of 1-methylbenzthiazole, 4 gm. of ethyl-ptoluene sulphonate and 16 cos. of pyridine. yielding 0.43 gm. of slate-grey matted crystals, melting at 267 C. with decomposition.

This dyestufl is a sensitiser for photographic silver halide emulsions and extends the sensitivity range of a silver-iodo-bromide emulsion uniformiy to about A 6400 A. and tailing oil to about i 7000 A.

3-methyl 2 ethyl-4-keto-5-(z-methyldihydrobenzthiazolylidene 2 ethylidene) thiazoiino-oxacyanine bromide from 0.80 gm. of 2-thio- S-methyl 4 keto-5-(2-methyldihydrobenzthiazolylidene- -ethylidenel-tetrahydrothiazoie, 0.33 gm. of l-methylbenzoxazole, 4 gms. of ethyl-ptoluene sulphonate and 15 cos. of pyridine, yielding 0.18 gm. of slate-blue matted crystals, melting at 283 C. with decomposition.

This dyestull' is a sensitiser for silver halide emulsion and extends the sensitivity range of a silver iodo-bromide emulsion to about A 6900 A. with a maximum at about A 6500 A.

3-methyl 1' ethyl-4-keto-5-(2-methyldihydrozenzthlazolylidene-l-ethylidene) thiazolino- \t-cyanine bromide from 0.80 gm. of 2-thio-3- methyl 4 keto-5-iz-methyldihydrobenzthiazolylidene-l-ethylidene)-tetrahydrothiazole, 0.36 gm. of quinaldine and 4 gms. of ethyl-p-toluenc sulphonate and 15 cos. of pyridine yielding 0.06 gm. of dark blue matted crystals, melting at 261 C.

This dyestuft is a sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver iodo-bromide emulsion weakly to about a 6200 A.

3.1'-diethyl 4 keto-5-(2-methyldihydrobenzthiazolylidene-l-ethylidenei thiazolinoisocyanine iodide, from 0.84 gm. of 2-thio-3-ethyl- 4-keto 5 (2-methyldihydrobenzthiazolylidenel-ethylidene) -tetrahydrothiazole, 0.36 gm. of lepidine, 3 gms. of ethyl-p-toluene sulphonate and 20 cos. of pyridine yielding 0.22 gm. of small gold crystals, melting at 280 C. with decomposition giving a blue-green solution in alcohol.

This dyestuii' is a sensitiser for photograhic emulsions and extends the sensitivity range of a silver iodo-bromide emulsion to about i 7800 A.

3.2 diethyl-4-keto-5-(z-methyldihydrobenzthiazolylidene l ethylidene)-thiazolinoselenocyanine-p-toluene sulionate from 0.84 gm. of 2- thio-3-ethyl 4 keto-5-(2-methyldihydrobenzthlazolylidene-l-ethylidene) tetrahydrothiazole, 0.49 gm. of l-methylbenzselenazole and 3 gms. oi ethyl-p-toluene sulphonate and 15 ccs. of pyridine yielding 0.35 gm. of deep blue matted crystals, melting at 284 C. with decomposition.

This dyestufl is a sensitiser for photographic silver halide emulsions and extends the sensitivity range or a silver lode-bromide emulsion to about i 6800 A. with a fairly uniform sensitivity to about A 6800 A.

3-methyl-2'-ethyi-4-keto-5 (2 methyldihydrobenzthiazolylidene-i ethylldene) -thiazolinoselenocyanine bromide from 0.80 gm, oi 2-thio-3- methyl-4-keto 5 (Z-methyldihydrobenzthiazolylidene-l-ethylidene) tetrahydrothiazole, 0.49 gm. of l-methylbenzselenazole, 3 gms. of ethyl-ptoluene sulphonate and 15 cos. of pyridine, yielding 0.42 gm. oi green-blue matted crystals, melting at 280 C. with decomposition.

This dyestui'l' is a sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver iodo-bromide emulsion to s,sse,ees

about i 6800 A. with a fairly uniform sensitivity to about A 6500 A.

3.2'-diethyi-4-keto-5 (2 methyldihydrobenzthiazolylidcne-i-ethylidene) -thiaaolino oxacya nine bromide from 2-thio-3-ethyl-4-keto-5 (2- methyldihydrobenzthiazolylidene-1 ethylidene) tetrahydrothiazole, 0.33 gm. of l-methylbenzoxasole, 4 gms. oi ethyl-p-toluene sulphonate and 15 cos. of pyridine yielding 0.18 gm. of slate-blue matted crystals, me ting at 263 C. with decomposition.

This dye is a sensitiser for silver halide photographic emulsions and increases the sensitivity range 01' a silver lode-bromide emulsion to about A 7000 A. with a maximum at about a 6400 A.

3.l'-diethyl-4-keto-5-(2 methyldihydrooenz thiazolylidene-l-ethylidene) -thiazolinocya nine bromide from 0.84 gm. of 2-thio-3-ethyl-4- keto--(2-methyldihydrobenzthiazolylidene 1 ethylidene) -tetrahydrothtazole, 0.36 gm. of quinaldine, 4.0 gms. of ethyi-p-toluene sulphonate, 15 cos. of pyridine yielding 0.90 gm. of dark blue matted crystals, melting at 262 C.

This dyestufl is a sensitiser for photographic silver halide emulsion and extends the sensitivity oi. a silveriodo-bromide emulsion weakly to about A 6400 A.

3.2'-diethyi-4-keto 5 (2 ethyldihydrobenz thiazolylidene-l-ethylidene) -thiazollno-oxa-cya nine bromide from 0.87 gm. of 2-thio-3-ethyl-4- keto-5 (2 ethyldihydrobenzthiazolylidene i ethyiidene) -tetrahydrothiazole and ethylbenzoxazoie, 4 gms. of ethyl-p-toluene sulphonate, 15 cos. of alcohol and 0.5 gm. of sodium acetate. yielding 0.09 gm. of dark blue matted crystals, melting at 269 C.

This dye is a sensitiser for photographic silver halide emulsions and increases the sensitivity of a silver iodo-bromide emulsion to about A 6800 A. with a maximum at about A 6000 A.

3.2 diethyl 4 keto-5-(2-ethyldihydrobenzthiazolylidene-l-ethylidene) thiazolino thia cyanine bromide from 0.87 gm. oi 2-thio-3-ethyl- 4'-keto-5- (2 ethyldihydrobenzthiazolylidene 1 ethylidene) -tetrahydrothiazole, 0.37 gm. of 1- methylbenzthiazole, 4.0 gms. of ethyl-p-toluene sulphonate. and 15 cos. of pyridine, yielding 0.45 gm. of dark blue matted crystals, melting at 241 C. with decomposition.

The dyestufl is a sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver iodo-bromide emulsion uniformly to about A 6500 A., gradually diminishing to zero at about 7\ 7200 A.

3.2'-diethyi-4-keto-5- (2 methyldihydrobenz oxazolylidene-l ethylidene) thiazolinothiacya nine bromide from 0.80 gm. of 2-thio-3-ethyl-4- keto-5-(2 methyidihydrobenzoxazolylidene 1 ethylidene) -tetrahydrothia27ole, 0.37 gm. of 1- rnethyl-benzthiazole, '4 gms. of ethyl-p-toluene sulphonate and 15 cos. of pyridine yielding 0.10 gm. oi grey green crystals melting at 259 C.

This dye is a sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver iodo-bromide emulsion uniformly to about A 6400 A. and gradually diminishing to about A 7100 A.

3.2'-diethyl-4-keto-5- (2 methyldihydrobenz oxazoiylidene-l-ethylidene) -thiazolino oxacya nine iodide from 0.80 gm. of 2-thio-3-ethyl-4- keto-5-(2 methyldihydrobenzoxazolylidene 1 ethylidene) -tetrahydrothiazole, 0.33 gm. of lmethyl-benzoxazole, 4 gms. of ethyl-p-toluene suiphonate and 15 cos. of pyridine, yielding 0.19

gm, oi dark olive green crystals. with a gold reflex melting at 255 C. v

The dye is a sensitiser for silver halide photographic emulsions and extends the sensitivity range oi a silver lode-bromide emulsion to about A 7200 A., with a maximum eflect to about A 6200 A.

8.1'-diethyl-4-keto-5-(2-methyldihydrobenzoxazolylidene-l-ethylidene) -thiaz0lino 41 cyaninc iodide irom 0.80 gm. of 2-thio-3-ethyl-4-kew-5- (-2 methyldihydrobenzoxaaolylidene i ethylidone) -tetrahydrothiazole, 0.36 gm. oi quinaldlne. 0.4 gm. of ethyl- -toluene sulphonate and 15 cos. of pyridine, yielding 0.08 gm. of dark blue matted crystals, melting at 267 C. with decomposition.

3-methyi- 1'- ethyl-4 -keto-5- (Z-methyldihydrobenzoxazolylidene 1 ethylidene) thiazolino-ipcyanine bromide from 0.76 gm. of 2-thio-3- methyl-4-keto-5 -(2-methyldihydrobenzoxazoiylldene-l-ethylidene)-tetrahydrothiazole. 0.36 gm. of quinaldine, 4 gms. of ethyl-p-toluene sulphohate and 15 cos. of pyridine yielding 0.06 gm. of dark blue matted crystals, melting at 262 C. with decomposition.

This dye is a sensitiser for silver halide photographic emulsions and extends the sensitivity of a silver iodo-bromide emulsion weakly to about A 6200 A.

3-methyl-2'- ethyl-4-keto-5- (2-methyidihydrobenzoxazolylidene-l-ethylidene) thiazolino oxacyanine iodide from 0.76 gm. of 2-thio-3-methyl- 4 keto-5 -(2-methyldihydrobenzoxazolylidenedethylidene) -tetrahydrothiazole, 0.33 gm. of 1- methylbenzoxazole, 4 gms. of ethyl-p-toluene sulphonate, and 15 cos. of pyridine, yielding 0.22 gm. of small green crystals, with a gold reflex melting at 270 C. with decomposition.

This dye is a, sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver lode-bromide emulsion to about A 6800 A. with a maximum at about )i 6200 A.

3-methyl-2' -ethyi4-keto-5- (2-methyidihydrobenzoxazolylidene 1 ethylidene) -thiazolinothiacyanine bromide from 0.76 gm. of 2thio-3- methyl-4-keto-5-(2-methyldihydrobenzoxazolylidene-1-ethylidene)-tetrahydrothiazole, 0.37 gm. of 1-methy1benzthiazole,4 gms. of ethyl-p-toiuene sulphonate, 15 cos. of pyridine, yielding 0.35 gm. of bright green crystals, melting at 284 C. with decomposition.

The dye is a sensitiser for silver halide photographic emulsions and extends the sensitivity range of a. silver lode-bromide emulsion to about A 6800 A., with a maximum at about i. 6200 A.

3.2'- diethyl-4-keto-5-(2 ethyldihydrobenzoxazolylidene-l-ethylidene) thiazolinothiacyanine iodide, from 0.83 gm. of 2-thio-3-ethyl-4-ireto-5- (2-ethyldihydrobenzoxazolylidene-l-ethylidene) tetrahydrothiazole, 0.37 gm. of l-methyibenzthiazole, 4 gms. oi ethyi-p-toluene sulphonate, 15 cos. of pyridine yielding 0.19 gm. of green crystals, melting at 247 C. with decomposition.

The dye is a, sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver iodo-bromide emulsion to about A 7500 A, with a maximum at about A 6600 A.

3 .2 -diethyi-4-keto-5- (Z-methyldihydrobenzoxazoiylidenel -ethylidene) thiazolino-oxacyanine iodide from 0.83 gm. of 2-thio-3-ethyl-4-keto-5- (2-ethyldihydrobenzoxazolylidene-l-ethyiidene) tetrahydrothiazole, 0.33 gm. of i-methylbenzoxscale. 4 gms. of ethyl-p-toluene sulphonate, 15 cos. of alcohol, 0.5 gm. anhydrous sodium acetate. yielding 0.08 gm. of small bright green crystals. melting at 280 C. with decomposition.

Enron 8 A (I c=cnj::cs

14.9 gms. of l-methyl-benzthiazole and 18.6 gms. oi methyl-p-toluene sulphonate were fused together for 2 hours at l-l40 C. Aiter cooling, 16.1 gms. of N-ethyl-rhodanic acid, 120 cos. of pyridine and 30 cos. acetic anhydride were added and the mixture was heated gently to effect solution and then boiled under reflux for 1% hours. It was then poured into cos. of methyl alcohol and a precipitate separated out on cooling. The precipitate was filtered off, washed with spirit and ether and recrystallised from methyl alcohol to give red brown crystals melting at 235 C. and giving orange alcoholic solutions. The reaction may be illustrated as follows:

Elton) BINDING AGENT? "Irish-so mii'as E 3 0810001] =3 (CIHISOJI N/ Acid Binding Agent 300 C. and giving purple-red alcoholic solutions. The reaction may be illustrated as follows:

CHI

C. Preparati n of he ium 4.33 gm. of the product obtained according to the process of Example 68 and 10 gins. of methyl-p-toluene sulphonate were fused together for 2 /2 hours at Mil- C. the mixture was then allowed to cool and 1.61 gins. of N-ethyl-rhodanic.

0.75 gm. of 3-ethyl-2-thio-4-keto-5-(2-methyldihydrobenzthiazolylidene) -tetrahydrothiazole, prepared by condensing l-methylthiolbenzthiazole methyl-p-toluene sulphonate with N-cthylrhodanic acid according to the general method oi s,ase,aca

Example In and 3 gm. of ethyl-ptoluene sulphonate were fused together for four hours at 150 C. The mixture was cooled and 0.50 gm. of N-ethylrhodanic acid and 30 ccs. of pyridine were added and the mixture was gently boiled under a reflux condenser for about 30 minutes, during which time a dyestufl separated out. After this the mixture was poured into a beaker and allowed to stand. The product which separated out was filtered off and washed with alcohol and purified by extraction with 100 ccs. of hot methyl alcohol, leaving 0.55 gins. of orange matted crystals, meltin at over 313 C.

The formula or the final product is believed to be:

Exlmrnn 8 0.73 gm. of 2-thio-3-ethyl-4-keto-5-(2-methyldi hydrobenzoxazolylidene) tetrahydrothiazole prepared according to Example 1A and 3 grns. of methyl-p-toluene sulphonate were fused together for four hours at 140 C. The mixture was allowed to cool aiter which 0.5 gm. of N-ethyl rhodanic acid and 15 cos. of pyridine were added and the mixture was boiled gently under a reflux condenser for about 30 minutes. The solution was then poured into a beaker and allowed to stand and cool when the dyestufi separated out. The dyestufl was filtered off, washed with alcohol and ether and purified by boiling with 90 cos. of methyl alcohol, leaving 0.41 gm. oi. orange matted crystals, melting at over 305 C.

The Iormula oi. the product is believed to be:

CiHl

This dye is a sensitiser for silver halide photographic emulsions and extends the sensitivity range oi a silver-iodobromide emulsion to about A 5800 A. with a maximum at about A 5200 A.

The following analogous products were also prepared in a similar manner. In each case the substituted tetrahydrothiazolas were obtained by the method of Example 1A from the corresponding methylthiol heterocyclic nitrogen quaternary salts and the corresponding N-alkyl rhodanic acids.

(A) From 0.75 gm. 2-thio-3-ethyl-4-keto-5-(1- methyldihydroquinolylidene) -tetrahydrothiazole. 3 gms. oi ethyl-p-toluene sulphonate and 0.50 gm. of N-ethyl rhodanic acid, yielding 0.34 gm. of crimson needles, melting at over 350 C.

This dye is a sensitiser for photographic silver halide emulsions and extends the sensitivity range of a. silver iodo-bromide emulsion to about i 6200 A. with a maximum at about 5900 A.

(B) From 0.73 gm. of 2 thio 3 methyl- 4-keto-5- (2 -methyl-dihydrobcnzthiazoiylidene) tetrahydrothiazole, 3 gins. oi ethyl-p-tolucne suiphonate, 0.5 gm. of N-ethylrhodanic acid and 20 cos. oi pyridine, yielding 0.52 gm. of orange matted crystals, melting at over 313 C.

(C) From 0.70 gm. oi, 3-thio-3-ethyl-4-keto-5- (2-methyldihydrobenzoxazolylidene) -tetrahydrothiazole, 3.0 gms. of ethyl-p-toluene sulphonate, 0.50 gm. of N-ethyl rhodanic acid and 15 cos. 0! pyridine yielding 0.45 gm. of orange matted crystals, melting at over 313 C.

(D) From 0.72 gm. of 2-thio-3-methyl-4-ketm 5- l-methyldihydroquinolylidene) -tetrahydrothiazole, 3 gm. of methyl-p-toluene sulphonate, 0.3 gm. of N-ethyl rhodanic acid and 15 cos. oi P dine yielding 0.63 gm. of crimson needles melti at over 305 C.

This dye is a sensitiser for photographic silver halide emulsions and extends the sensitivity range of a silver iodo-bromide emulsion to about i 6000 A.

(E) From 0.72 gm. of 2-thio-3-methyl-4-keto- 5-(3-methyl dihydroquinazolylidene 4-) tetrahydrothiazole, 3 gms. oi ethyl-p-toluene sulphonate, 0.5 gm. of N-ethyl-rhodanic acid and 15 cos. 0! pyridine yielding 0.22 gm. of very small dark blue crystals, melting at over 306 C.

This dyestufi is a sensitiser for photographic silver halide emulsions and extends the sensitivity of a silver lode-bromide emulsion to about A 6000 A. with a maximum at about A 5750 A.

EXAMPLE 9 0.84 gm. of 2-thiol-3-ethyl-4-keto-5-(2-methyldihydrobenzthiazolylidene-l-ethylidene) -tetrahy drothiazole prepared by condensing N-ethyl rhodanic acid with l-w-acetam1idovin.vlbenzthiazole methyl-p-toluene sulphonate according to the method of Example 3A were fused together with 3 grns. of ethyl-p-toluene sulphonate for 4 hours at C. The mass so obtained was allowed to cool and 0.41 gm. of N-ethyl-rhodanic acid were added together with 15 cos. of pyridine and the mixture was boiled gently under a reflux condenser for about 30 minutes. The mixture was poured into a beaker and allowed to stand and cool. The dyestufi separated out and was illtered ofl and washed with alcohol and purified by extracting repeatedly with hot methyl alcohol until the yellow impurity was removed, leaving 0.20 gm. of small very dark green crystals, meltin! at 302 C. decomposing at 308 C.

The formula of this compound is believed to be:

This dyestufi is a sensitiser for photographic allver halide emulsions and extends the sensitivity range of a silver iodo-bromide emulsion to about a 7000 A. with a maximum at about A 6500 A.

The following analogous compounds were prepared by the same general method from the materials indicated. Except where otherwise stated in each case the substituted tetrahydrothiazole was prepared by the methods described in Exampies 3A and 43 from the corresponding N-alkyl rhodanic acids and the quaternary ammonium salts of the corresponding ip-acetanilidovinylheterocycllc nitrogen compounds.

(A) 0.80 gm. of 2-thio-3-ethyl-4-keto-5-(2- methyldihydrobenzoxazolyiidene -l ethylidene) tetrahydrothiazole obtained by condensing N- ethyl-rhodanic acid with l-u-aoetanilido vinylbenzoxazole methyl-p-toluene sulphonate in the presence of pyridine, 3 gins. oi ethyl-p-toluene sulphonate, 0.41 gm. N-ethyl rhodanic acid and 15 ccs. of pyridine yielding 0.20 gm. oi shinlng gold brown crystals. melting at 312 C.

This dye is a sensitiser for photographic silver halide emulsions and extends the sensitivity range 01' a silver iodo bromide emulsion to about A 6600 A. with a maximum at about A 6200 A.

(B) From 0.80 gm. of 2-thio-3-methyl-4-keto. -(2- methyldihydrobenzthiazolylidene-l ethylidene) -tetrahydrothiazole, 0.4 gm. of ethyl-p-toiuene sulphonate, 0.41 gm. of N-ethyl-rhodanic acid and 15 cos. of pyridine and yielding 0.17 gm. of dark blue crystals, melting at over 300' C.

This dye is a sensitiser for photographic silver halide emulsions and extends the sensitivity range of a silver iodo-bromide emulsion to about A 6700 A. with a maximum at about A 6400 A.

(C) From 0.76 gm. oi 2-thlo-3-methyl-4-keto- 5-(2-methyldihydrobenzoxazolylidene 1 ethyliclene) -tetrahydro-thiazo1e, 3 gms. of ethyl-p-toluene sulphonate, 0.41 gm. of N-ethyl-rhodanic acid and 15 ccs. of pyridine, yielding 0.18 gm. of small dark brown crystals, melting at over 312' C.

This dye is a sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver lode-bromide emulsion to about A 6400 A. with a maximum at about A 6200 A.

(D) From 0.79 gm. of 2-thio-3-methyl-4-keto- 5- i-methyldihydroquinolylidene-z ethylidene) tetrahydrothiazole, prepared by condensing quinaldine methiodide with 5-u-acetanilido-metl'iylene-N-methyl-rhodanic acid, 3 gm. oi ethyl-ptoluene sulphonate, 0.5 gm. of N-ethyl-rhodanic acid and 15 ccs. oi pyridine yielding 0.34 gm. of small purple crystals, melting at over 305 C.

Exams:

1.75 gms. of the product obtained according to Example 9 above were fused with 4 gms. oi methyl-p-toluene sulphonate for tour hours at 140-150 C. The mixture was then allowed to cool and 0.62 gm. of N-ethyl-rhodanic acid and cos. 0! pyridine were added after which the mixture was boiled gently under a reflux condenser for about thirty minutes. The resulting solution was poured into a beaker and allowed to stand and the dyestufl which separated out was filtered 0E and washed with alcohol and ether leaving 1.54 gms. oi crude dye. 0.5 gm. 01' this crude dye were purified by boiling with methyl alcohol and filtering, leaving 0.38 8m. 0! a blackish-purple powder, melting at over 300 C.

This dye is a sensltiser for silver halide photographic emulsions and extends the sensitivity range of a silver lode-bromide emulsion to about A 7200 A. with a maximum at about A 6500 A.

The formula oi this compound is believed to be:

0.84 gm. of the 2-thlo-3-ethyl-4 keto 5 (2- methyldihydrobenzthiazolyiidene 1-ethylidene)- tetrahydrothiazole was produced by the method a,sss,eea

of Example 4A from l-u-acetanilidovlnylbensthiazole methol-p-toluene sulphonate and N- ethyl-rhodanic acid, were fused with 3 gms. oi methyl-p-toluene sulphonate for four hours at -150 C. The mixture was allowed to cool and'0.44 gm. oi l-phenyl-3-methyl-5-pyrazolone and 15 ccs. of pyridine were added and the mixture was boiled gently under a reflux condenser for about 20 minutes. The resulting solution was poured into a beaker containing a little alcohol and the whole was allowed to stand and cool. A dyestufl crystallised out on cooling and was illtered on and washed with alcohol and ether and purified by boiling with 200 ccs. of methyl alcohol and filtered oil, leaving 0.35 gm. of blue crystals melting at 287 C.

The formula of the dyestufl is believed to be:

This dyestui'! is a sensitiser for silver halide photographic emulsions and extends the sensitivity range of a silver iodo-bromide emulsion to about A 6700 A. with a uniform band to about A 6200 A.

Exmtx 11A with a maximum at about A 5700 A.

Exsurts HE A similar compound was prepared by the same general method from 0.74 gm. of 2-thio-3-methyl- 4-keto-5 (2 methyldihydrobenzthiazolylidene) tetrahydrothiazole prepared according to the method described in Example 1A from i-methylthiolbenzthiazole methyl-p-toluene sulphonate and N-methyl rhodanic acid, 5 gms. oi methyl-ptoluene sulphonate, 0.44 gm. of 1-phenyl-3- methyl-5-pyrazolone and 15 cos. of pyridine yielding 0.68 gm. of minute deep yellow crystals, melting at 286 C. and giving a lemon yellow solution in alcohol.

This dye is a sensitiser for photographic silver halide emulsions and extends the sensitivity range of a silver chloride emulsion to about A 5100 A.

with a maximum at about A 4900 A.

Enllrts i2 3-ethyl-4-keto 5 (2 methyldihydrobenzthiazolylidene) -thiazolino-2'.2'-ketazine. 0.77 gm. of 2-thio-3-ethyl-4-keto-5-(2-methyl dihydrobenzthiazolylidene)-tetrahydrothiazole prepared according to the method of Example 1A from i-methylthiolbenzthiazole methyl-p-toluene sulphonate and N-ethylrhodanic acid, were fused together with 3.0 gm. of methyi-p-toluene sulphonate for four hours at 140-150 C. The mass was allowed to cool and 0.13 gm. of hydrazine hydrochloride and 16 cos. of pyridine were added and the mixture was boiled gently under a reflux condenser for about 25 minutes. The mixture was then poured into a beaker and allowed to stand after which the product which separated out was filtered oil, washed with alcohol and ether and then purified by boiling with 200 cos. of methyl alcohol and filtered leaving 0.35 gm. of a lemon yellow powder melting at over 292' C.

The product is believed to have the formula:

.EXAIIPLI 12A This dye is a sensitiser for photographic silver halide emulsions and extends the sensitivity range or a silver iodo-bromide emulsion to about It 6200 A. and of a silver chloride emulsion to about 7\ 5400 A. with a maximum at about A 5100 A.

Example: 13

B-methyl-Z '-ethyl-4-keto-5- p-dimethylaminobenzallethiazolinothiacyanine iodide. 0.71 gm. 2+.thio-3-meth'yl-4-keto-5- (p dimethylaminobenzal) -tetrahydrothiazole prepared by the condensation of N-methyl-rhodanic acid and p-dimethylaminobenzaldehyde were fused with 3 gms. oi' ethyl-p-toluene suiphonate and 0.37 gm. of l-methylbenzthiazole for four hours at 140150 C. The mass was then allowed to cool and 15 cos. oi pyridine were added and the mixture was gently boiled under a reflux condenser for about 30 minutes. The mixture was then poured into a beaker and allowed to stand and cool. The liquid was then filtered OE and mixed with an aqueous solution oi potassium iodide when the dyestuil separated out. This dyestufl was filtered oil and washed with alcohol and ether and finally purifled by boiling with benzene and filtering. The residue was recrystallised from two lots of 90 cos. a! boiling methyl alcohol yielding 0.20 gm. of purple matted crystals melting at 286 C.

1s The compound is believed to be represented by the formula:

This dye is a sensltiser for photographic silver halide emulsion and extends the sensitivity range of a silver iodo-bromide emulsion weakly to about Emma: 14

3.2 diethyl 4-keto-5-(2-methyldlhydrobenzthiazolylidenei-thiazolinothiacyazine p-toluene sulphonate. 0.77 gm. of 2-thio-3-ethyl-4-keto-5- (2 methyldihydrolylidene) tetrahydrothiazole, prepared according to the method of Example 1A from l-methyithiolbenzthiazole methyl-p-toluene sulphonate and N-ethyl-rhodanic acid, were fused together with 0.38 gm. of

l-aminobenzthiazole and 3 gms. of ethyl-ptoluene sulphonate for four hours at 140-150 C.

The mixture was allowed to cool. 15 cos. of pyridine were added and the whole was then boiled gently under a reflux condenser for about thirty minutes, and then poured into a beaker and diluted with water. The dye which precipitated out was filtered oil, washed with alcohol and then with hot benzene and agai with alcohol and finally with ether.

The dye wa boiled with 10 cos. of methyl alcohol and filtered and crystallised, yielding 0.28

gm. of vermiilion plate crystals melting at 222 C. and giving a lemon yellow solution in alcohol. The formulae of this dyestuil is believed to be as m follows:

CH: (1: H N\ Exnrrns 14A iodide, yielding 0.20 gm. of dark green long narrow plates, melting at 286 C.

Exlmru: 15

3.3 -diethyl-4.4' -dik8t0 5.5'-di(2-methyldihydrobenzthiazolylidene) thiazolinocyazine bromide. 0.75 gm. of 2-thio-3-ethyl-4-keto-5-(2- methyldihydrobenzthiamlylidene) tetrahydrothiazole prepared by the method of Example 1A from i-methylthiolbenzthiazole methyl-p-toluene sulphonate and N-ethyl-rhodanlc acid were fused with 3 gms. of methyl-p-toluene sulphonate for 3 hours at 150 C. The mixture was allowed to cool and 0.40 gm. of finely ground ammonium nitrate and 15 cos. of pyridine were added and the mixture was boiled gently under a reflux condenser for about 45 minutes. The mixture was poured into a solution of potassium bromide and allowed to stand. The precipitate which was formed was filtered oil and washed with alcohol, hot benzene and ether and wa finally purified by crystallising from 50 cos. of methyl alcohol, yielding 0.17 gm. scarlet crystals with a gold reflux melting at 217 C.

The formula of the dye is believed to be:

3.3'- diethyl-4.4'-diketo-5.5-di(2 methyldihydrobenzthiazclylidene) thlazolino 6.6 orthophenylene-carbocyanine p toluene sulphonate. 0.77 gm. of 2-thio-3-ethyl-4-keto-5-(2-methyldihydrobenzthiazolylidene) tetrahydrothiazole prepared according to the method of Example 1A from l-methylthiolbenzthiazole methyl-p-toluene sulphonate and N-ethyl-rhodanic acid were fused with 3.0 gms. of ethyl-p-toluene sulphonate for four hours at 140 to 150 C. The mixture was allowed to cool and 1 cc. of indene and cos. of pyridine were added, and the mixture gently heated on a water bath under a reflux condenser for 45 minutes. The contents of the flask were then poured into a beaker and left to crystallise. The dyestuif which crystallised out was filtered oil, washed with a little alcohol and then washed repeatedly with hot benzene and then again with alcohol and finally with ether.

The residue was boiled with 10 cos. of methyl alcohol and filtered on, the residue leaving 0.013 gm. of greenish-brown dyestufl, melting at over 302' C. and giving a blue solution i alcohol.

The formula of this dye is believed to be as follows:

EXAMPLE 17 3.3'-diethyl-4.4 '-diketo-5.5 -di- (2-methyldihydrobenzthlazolylidene) thiazolino-carbocyanlne- D-toluene sulphonate. 0.77 gm. of 2-thio-3-ethyl- 4-keto-5-(2 methyl di-hydrobenzthlazolidene) tetrahydrothiazole prepared according to Example 1.4 from l-methyl-thiolbenzthlazole methylp-toluene sulphonate and N-ethyl-rhodanlc acid were fused with 3.0 gms. of ethyl-p-toluene sulphonate for four hours at 140-150 C. The mixture was then allowed to cool and 6 ems. of glutaconic acid and 15 cos. of pyridine were added and the mixture boiled gently for 45 minutes under a reflux condenser. The resulting solution was poured into a beaker and left to crystalllse. The precipitate was filtered off, washed with alcohol, hot benzene, alcohol and finally with ether.

The residue was then boiled with 10 cos. of methyl alcohol and filtered leaving 0.35 gm. of a dirty brown dyestufl, melting at over 300 C. giving a blue solution in alcohol.

The dyestuif is believed to be represented by the following formula:

0.77 gm. of 2-thio-3-ethyl-4-keto-5-(2' -methylbenzthiazolylidene) -tetrahydrothiazole prepared according to Example 1A from l-methylthiolbenzthiazole methyl p-toluene sulphonate and N- ethyl-rhodanic acid, were fused with 3 ans. of mpthyl-p-toluene sulphonate for three hours at 140-150 C. The mixture was then cooled and 0.3 gm. of thiohydantoin and 12 cos. of pyridine were added and the mixture gently boiled under a reflux condenser for 25 minutes. The resulting mixture was poured into a beaker and allowed to cool when the dyestuff crystallised out. The solution was then diluted with water to complete the precipitation.

The dyestulf was filtered off, washed with alcohol and ether and purified by boiling with cos. of methyl alcohol and filtered off, leaving 0.32 gm. of small orange crystals melting at 274 C. and giving an orange yellow solution in alcohol.

The formula of this dye is believed to be as follows:

The dye is a sensitiser for silver halide photographic emulsions and extends the sensitivity of a silver iodo-bromlde emulsion to about A 5400 A. with a maximum at about 7i 4800 A.

Exmu 10 3-methyl-2'-ethyl-4-keto-5 (ll-methyldihydrobenzthiazolylidene 1 ethylidene) -oxazolinothiacyanine bromide. 0.76 gm. of 2-thio-8-methyl- 4 keto-S- 2-methyldihydrobenzthiazolylidene-1- ethylidene) -tetrahydro-oxazole prepared according to the method of Example 3A from 1-0- acetanilidovinyl benzthiazole and 2-thio-3- methyl-4-keto-tetrahydro-ox.azole, were fused with 0.38 gm. of l-methylbenzthiazole and 3 gm. of ethyl-p-toluene sulphonate for 4 hours at C. The mixture was allowed to cool and 15 cos. of pyridine was added, the whole was boiled gently under a reflux condenser for 20 minutes. The solution thus obtained was poured into a beaker containing potassium bromide solution and allowed to stand and crystailise. The precipitated asespcs Calls B The dyestuii' is a sensitiser for silver halide photographic material and extends the sensitivity range of a silver halide emulsion to about A 6600 A. with a maximum at about A 6100 A.

Exams 20 3.2'-diethyl-4-keto S-(Z-ethyldihydrobenzthiazolylidene-l-ethylidene) -oxazolino-thia-cyanine iodide, was obtained by the same general method as the previous example from 0.80 gm. of 2-thio- 3-ethyl-4-keto-5-(2-methyldihydrobenzthiazolylidene-i-ethylidene) -tetrahydro-oxazole prepared according to the general method of Example 3A from 1-o-acetanilidovinyl-benzthiazole and 2- thio3-ethyl-4-keto-tetrahydro-oxazole, 0.37 gm. of i-methylbenzthiazole and 3 gms. oi ethyl-ptoluene sulphonate and 15 cos. of pyridine yielding 0.01 gm. of a blackish-purple dyestufi, melting at 245 C. with decomposition.

This dye is a sensitizer for silver halide photographic emulsions and extends the sensitivity range of a silver iodo-bromide emulsion to about a 6500 A. with a maximum at about A 6000 A.

Emma: 21

3.3'-diethyl 4.4'-diketc-5.5'-di-(2 methyldihydrobenzthiazolylidene)-thiazolino carbocyanine-p-toluene sulphonate. 0.75 gm. of 2-thio- 3-ethyl-4-keto-5-(2 methyldi-hydrobenzthiazolylidene-tetrahydrothiazole obtained from 1- methylthiolbenzthiazole-methyl p toluene sulphonate and N-ethyl-rhodanic acid according to the method of Example 1A, were fused with 3 gms. of methyl-p-toluene suiphcnate for three hours at 150 C. The mixture was cooled and 1 cc. of crotonic anhydride and 15 cos. of pyridine were added and the mixture was boiled gently under a reflux condenser for 45 minutes during which time the dyestufl. separated out. The mixture was then allowed to cool and the dyestufi was filtered off and washed with alcohol, hot benzene and ether and was finally purified by boiling with cos. of methyl alcohol leaving 0.09 gm. of dark gold crystals, melting at 303 C. with decomposition.

This dye is the same as that produced in Example 1'1.

We claim:

1. A process for the production of a dyestufl comprising condensing quinaldine methiodide with S-acetanilido-methenyi-N-methylrhodanic acid in the presence of pyridine and fusing the product with quinaldine and ethyl-p-toluene sulphonate and heating the fused product with pyridine.

2. 3-methyl-l'-ethyl-4-keto-5-(1 methyl-dihydroquinolylidene-2-ethy1idene) thiazolino-ipcyanine bromide having the structural formula 3. A process for the production of a dyestuif wherein 2-thio-3-ethyl-4 keto-E-(l-methyl-dihydroquinolylidene) -tetrahydrothiazole and ethyl-p-toluene sulphonate are fused together and the fused mixture heated with N-ethyl rhodanic acid and pyridine.

4. 2-thio-3-ethyl-4-keto-5-[3'-ethyl-4' ketc- 5'-(1" methyldihydroquinolylidene 2" ethylidene) tetrahydrothiazolylidenel tetrahydrothiazoie having the structural formula /C=S --N 5. The method of producing dyestufls which comprises condensing a compound of the general formula:

where p is a numeral taken from the group consisting of 0 and 1, n is a numeral taken from the group consisting of 0 and 1, m is a positive small integer, R1 and R: are hydrocarbon groups, X is the residue of a heterocyclic nitrogen compound of the type used in the preparation oi cyanine dyes, Y is an atom selected from the group consisting of oxygen and sulphur and Z is an atom selected from the group consisting of sulphur and selenium, with an alkyl salt to convert the group Z into a reactive group, and condensing the product with an organic compound containing a group selected from the class consisting of reactive methyl and reactive methylene groups.

6. The method of producing dyestuffs which comprises condensing a compound of the general formula:

where p is a numeral taken from the group consisting 01' 0 and 1, n is a numeral taken from the group consisting of 0 and 1, m is a positive small integer, R1 and R: are hydrocarbon groups, X is the residue of a heterocyclic nitrogen compound of the type used in the preparation of cyanine dyes, Y is an atom selected from the group consisting of oxygen and sulphur and Z is an atom selected from the group consisting of sulphur and selenium, with an alkyl salt to convert the group Z into a reactive group, and condensing the product with a heterocyclic organic compound containing a group selected from the class consisting oi reactive methyl and reactive methylene groups.

'7. The method of producing dyestuffs which comprises condensing a compound of the general formula:

where p is a numeral taken from the group consisting of and l, n is a numeral taken from the group consisting of 0 and 1, m is a positive small integer, R1 and R: are hydrocarbon groups, X is the residue oi a heterocyclic nitrogen compound of the type used in the preparation of cyanine dyes, Y is an atom selected from the group consisting of oxygen and sulphur and Z is an atom selected from the group consisting of sulphur and selenium, with an alkyl salt to convert the group 2 into a reactive group, and condensing the product with an organic compound of the general formula:

where p is a numeral taken from the group consisting of 0 and 1, n is a numeral taken from the group consisting of 0 and 1, m is a positive small integer, R1 and R: are hydrocarbon groups, X is the residue of a heterocyclic nitrogen compound of the type used in the preparation of cyanine dyes, Y is an atom selected from the group consisting of oxygen and sulphur and Z is an atom selected from the group consisting of sulphur and selenium, with an alkyl salt to convert the group Z into a reactive group, and condensing the product with an alkyl quaternary salt or a heterocyclic nitrogen compound of the type used in the preparation of cyanine dyes having a reactive methyl group in a position selected from the group consisting of the a and '7 positions to the heterocyclic nitrogen atom.

9. The method of producing dyestuffs which comprises condensing a compound of the general formula:

where p is a numeral taken from the group consisting of 0 and 1, n is a numeral taken from the group consisting of 0 and 1, m is a positive small integer, R1 and R: are lower alkyl radicals, X is the residue of a heterocyclic nitrogen compound of the type used in the preparation of cyanine dyes, Y is an atom selected from the group consisting of oxygen and, sulphur and Z,

where p is a numeral taken from the group consisting of 0 and 1, n is a numeral taken from the group consisting of 0 and l, m is a positive small integer, R1 and R2 are hydrocarbon groups, X is the residue of a heterocyclic nitrogen compound of the type used in the preparation of cyanine dyes, Y is an atom selected from the group consisting of oxygen and sulphur and Z is an atom selected from the group consisting of sulphur and selenium, with an alkyl salt to convert the group Z into a reactive group, and condensing the product with an alkyl salt of 2-methyl-benzthiazole.

12. The method of producing dyestufis according to claim 11 wherein the alkyl salt employed is an alkyl-p-toiuene sulphonate.

13. The method of producing dyestuffs which comprises fusing together a compound of the general formula:

where p is a numeral taken from the group consisting of 0 and l, n is a numeral taken from the group consisting of 0 and 1, m is a positive small integer, R1 and R2 are hydrocarbon groups, X is the residue of a heterocyclic nitrogen compound of the type used in the preparation of cyanine dyes, Y is an atom selected from the group consisting of oxygen and sulphur and Z is an atom selected from the group consisting oi sulphur and selenium, an alkyl-p-toluene sulphonate and a heterocyclic nitrogen compound of the type used in the preparation of cyanine dyes, having a, reactive methyl roup in a position selected from the group consisting of the a and 1 positions to the heterocyclic nitrogen atom, and completing the reaction by heating the fused mass in the presence of a solvent and acid binding agent.

14. The method of producing dyestufis which comprises fusing together a compound of the general formula:

where p is a numeral taken from the group consisting of 0 and 1, n is a numeral taken from the group consisting of 0 and 1, m is a positive small integer, R1 and R: are hydrocarbon groups, X is the residue of a heterocyclic nitrogen. compound of the type used in the preparation of cyanine dyes, Y is an atom selected from the group consisting of oxygen and sulphur and Z is an atom selected from the group consisting oi sulphur and selenium, an alkyl-p-toluene sulphonate and an organic compound of the general formula:

riz-co-cm where in is the residue of a li-membered heterocyclic nitrogen ring and R: is a group selected from the group consisting of hydrogen and hydrocarbon groups, and completing the reaction by heating the fused mass in the presence of a solvent and acid binding agent.

15. The dyestuiis of the general formula:

wherein m is a positive small integer, p and n are numerals taken from the class consisting of and 1, R1, R2 and Rs are lower alkyl radicals, X is the residue of a heterocyclic nitrogen compound of the type used in the preparation of cyanine dyes, Y and Y are atoms taken from the group consisting of oxygen and sulfur, and Z is an atom selected irmn the group consisting of suli'ur and selenium.

18. The dyestufls of the general formula:

wherein R1, R: and R: are lower allnvl radicals, x is the residue of a hetcrocyclic nitrogen nucleus of the type used in the production or cyanlne dyes.

17. The dyestufls o! the general formula:

wherein m is a. member taken from the group consisting oi 0 and a positive small integer, p and n are numerals taken from the class consisting of 0 and 1, R1, Ra, R: and R4 are lower alkyl radicals and X and X are the residues oi heterocyclic nitrogen compounds or the type used in the production of cyanine dyes, Y and Y are atoms taken from the group consisting of oxygen and sulfur, and K is an acid radical.

1B. A process for the production of dyestufls remainder o! a heterocyclic system of the type used in cyanine dyes, R is alkyl, and R: is a memher of the group consisting oi alkyl. aryl and aralkyl.

19. A process for the production of dyestufls comprising treating with an alkyl salt a compound oi the general formula:

position taken from the group consisting of the a and 7 positions to the ring nitrogen atom. 20. The dyestuffs o! the general formula:

where x and X1 are the remainders or heterocyclic systems 01' the type used in cyanine dyes, n and p are positive integers less than 3, R and Rs are alkyl, and R2 is a member oi the group consisting oi alkyl, aryl and aralkyl.

21. A product having the general formula:

it. n.

where x is the remainder of a heterocyclic syscomprising treating with an alkyl salt a com-,

pound of the general i'ormula:

I a C=(CH--CH)--i=C-S N/ o= :=s i N where n is a positive integer less than 3, x is the tem oi the type used in cyamne dyes, n is a positive integer less than 3, R and R: are alkyl groups, and R: is a member of the group consisting of alkyl, aryl, and aralkyi.

22. A product of the general formula:

wherein d and 1:. each represents a pomtive integer of from one to two, Q represents a member selected from the group consisting of oxy n and sulfur atoms, R represents an alkyl group, R: represents a member selected from the group consisting of alkyl, aralkyl and aryl groups, x represents the remainder 01' a heterocyclic system of the type used in cyanine dyes and Z represents the remainder oi a heterocyclic system.

23. A process for preparing a dye comprising condensing, in the presence oi an acid-binding agent, a. heterocyciic organic compound containing a ketomethylene group with a compound of the' following general tormuia:

111 enion wherein d and 11 each represent a positive integer of from one to two, Q represents a member selected from the group consisting of oxygen and sulfur atoms, R and R: each represent an alkyl group, R2 represents a member selected from the group consisting oi alkvl, aralkyl and aryl groups and X represents the remainder of a heterocyclic system of the type used in cyanine dyes.

24. A process for preparing a dye comprising condensing. in the presence oi an acid-binding agent, malonic acid with a compound of the following general formula:

DOUGLAS JAMES FRY. JOHN DAVID KENDALL.

Certificate of Correction Patent N0. 2,388,963.

November 13, 1945.

DOUGLAS JAMES FRY ET AL.

It is hereby certified that errors appear in the rinted specification of the above numbered patent requiring correction as follows:

age 1, first column, line 40, for

that portion of the formula reading CH),,, read 0H), page 2, first column, line 51, for 461,688 read 461,668; page 5, second column, line 49, for 5400 A read 5500 A; page 6, second column, line 73, in the formula, for 0 H, read (LI-1,; page 7, second column, line 35, for that portion of the formula reading NOeHi lie Page 9, first column, line 30, for CH-CS read CH=CS; page 10, first column, line 31, for iodi-bromide read lode-bromide; and second columni line 24, for drozenzthiazol lidene read drobenzth'iazolylidem;

age 11, first co umn, line 22, for

0.90 rea 0.0.9; page 13, first column, line 67, or 350 C. read 305 C'.; page 14, first column, line 75, strike out the word was; page 16, first column, line 17, for "refiux read reflex; page 19, first column, line 22, in the formula, for CON read OC'N; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 7th day of May, A. D. 1946.

[sun] LESLIE FRAZER,

First Assistant Commissioner of Patents. 

